Tiny, tiny red worm?

[Oshria]

While cleaning the two office Freshwater ten gallon tanks I noticed a very tiny, hardly visable red worm swimming around. I can't figure out what they are. Any ideas?

 

[BlueStraggler]

Turn up your heater to about 83 to 84 if it will not harm the fish you keep in there. Those are parasites and turning the heat up a little should quicken their life cycle and kill them.

Unless it is not a worm at all but a piece of....poop. lol. Some look like that.

 

[Oshria]

I've never seen poop swim around the top of the tank...lol, Thanks. I just found out that the second tank is full of these little worms. I'm doing a total change of water and cleaning everything. Do you think this will help? Are they harmful to people?